Glass flake

Abstract

The present invention provides a glass flake that is substantially free of boron trioxide (B 2 O 3 ), barium oxide (BaO), zinc oxide (ZnO), and fluorine (F) and has sufficient heat resistance and good formability for glass flake. The glass flake of the present invention includes a glass composition that contains the following components, expressed in mol %; 50≦SiO 2 ≦65; 4≦Al 2 O 3 <12; 5≦SrO≦25; 10<(MgO+SrO)≦30; 20≦(MgO+CaO+SrO)≦45; and 0<(Li 2 O+Na 2 O+K 2 O)<2; wherein the glass composition is substantially free of B 2 O 3 , BaO, ZnO, and F. This glass flake is useful for resin compositions, paints, cosmetics, ink compositions, and the like.

1. A glass flake comprising:
 a glass composition containing the following components, expressed in mol %; 
 50≦SiO 2 ≦65; 
 4≦Al 2 O 3 <12; 
 5≦SrO≦25; 
 10<(MgO+SrO)≦30; 
 20≦(MgO+CaO+SrO)≦45; and 
 0<(Li 2 O+Na 2 O+K 2 O)<2, 
 wherein the glass composition is substantially free of B 2 O 3 , BaO, ZnO, and F. 
 
     
     
       2. The glass flake according to  claim 1 , wherein MgO and CaO in the glass composition are in the following respective ranges, expressed in mol %,
 0≦MgO≦15, and 
 10≦CaO≦35. 
 
     
     
       3. The glass flake according to  claim 1 , wherein:
 SiO 2 , Al 2 O 3 , MgO, CaO, and SrO in the glass composition are in the ranges, expressed in mol %, 
 55≦SiO 2 ≦65, 
 4≦Al 2 O 3 ≦10, 
 0≦MgO≦10, 
 10≦CaO≦30, and 
 5≦SrO≦20; and 
 MgO+SrO and MgO+CaO+SrO are in the ranges, expressed in mol %, 
 10<(MgO+SrO)≦20, and 
 25≦(MgO+CaO+SrO)≦35. 
 
     
     
       4. The glass flake according to  claim 1 , wherein a working temperature of the glass composition is 1250° C. or lower. 
     
     
       5. The glass flake according to  claim 1 , wherein a temperature difference obtained by subtracting a devitrification temperature of the glass composition from a working temperature thereof is at least 50° C. 
     
     
       6. The glass flake according to  claim 1 , further comprising a coating film, formed on a surface of the glass composition, of at least one selected from a metal and a metal oxide. 
     
     
       7. The glass flake according to  claim 6 , wherein the metal is at least one metal selected from the group consisting of nickel, gold, silver, platinum, and palladium. 
     
     
       8. The glass flake according to  claim 6 , wherein the metal oxide is a metal oxide containing at least one metal selected from the group consisting of titanium, aluminum, iron, cobalt, chromium, zirconium, zinc, tin, and silicon. 
     
     
       9. A resin composition comprising a glass flake according to  claim 1 . 
     
     
       10. A paint comprising a glass flake according to  claim 1 . 
     
     
       11. A cosmetic product comprising a glass flake according to  claim 1 . 
     
     
       12. An ink composition comprising a glass flake according to  claim 1 .